Asthma is a common chronic inflammatory disorder of the distal airways characterized by recurring symptoms, airway inflammation, and reversible airflow constriction. It is considered a collection of various phenotypes (characteristics) instead of a single disease. Currently, there is no comprehensive phenotyping specific to older adults with asthma that considers multiple factors relevant to this population. Divergent asthma phenotypes and exposure to unique environmental triggers may affect asthma control in the elderly. In addition, factors contributing to asthma quality of life in the elderly have not been wll explored. The aims of our study are to: (1) develop and systematically implement a phenotyping algorithm in older adults with asthma; (2) longitudinally investigate the effects of asthma phenotypes and volatile organic compounds (VOCs) exposures on asthma control in older adults with asthma; and (3) develop a predictive model for asthma quality of life for older adults with asthma. Sub-aims are to explore the impact on moving from community-based to congregate living settings (e. g, assisted living) on the course of asthma in older adults and to identify barriers to successful asthma medication management. One hundred ninety participants 60 years of age or older will be enrolled. Inclusion criteria are: meet standard diagnostic criteri for asthma, non-smokers, have no other chronic respiratory diseases, do not reside in a skilled nursing facility, and have not recently had a major a medical illness. At baseline, participants wil complete spirometry bronchodilator responsiveness, fractional exhaled nitric oxide, methacholine challenge (if not completed within past 5 years), allergic sensitization, Immunoglobulin E (IgE), and sputum analysis, as well as standardized questionnaires to assess asthma control, quality of life, knowledge, and self-efficacy. Within 30 days, an in-home environmental assessment will be conducted to obtain data on VOCs, air particulates, moisture, temperature, humidity, pests, and an asthma home environment checklist. At 9 and 18 months, in-home data will be collected on participants' pulmonary status, asthma control, and asthma quality of life. At 9-months, participants will also complete the measures of medication management. At 18-months, we will conduct follow-up in-home environmental assessments collecting the same data we collected at baseline. Participants who have moved to congregate living facilities will be asked open-ended questions about their perception of the effects of the move on the course of their asthma. Using factor analysis, we will perform a comprehensive phenotypic characterization that will include a wide range of demographics, asthma-specific knowledge and self-efficacy, and biomarkers. Predictive models for asthma control and asthma quality of life will be identified using generalized linear mixed-effects modeling. The findings of this study will be used in future research to develop and test the efficacy of patient-centered interventions for older adults with asthma to improve asthma control and enhance quality of life.